One Pump Man
by KartyParty
Summary: After the destruction of A-City, Genos finds himself in the middle of an awkward series of body malfunctions. He enlists the assistance of Saitama to help him through the art of "sparring". Will Genos discover the cure for what ails him?


"I'm home, Genos."

Saitama had returned, his mousey voice projecting across the tiny studio room to greet me. My guess is from a lazy day spent on patrol. Unfortunately for us, business with the Hero Association had been a little sparse since our run-in with the Dark Matter Thieves and many heroes were designated to keep watch on the streets as A-City was rebuilt.

As a consequence, money was pretty tight.

S-Class heroes such as myself were well looked after by the Hero Association during these dire times; amenities, discounts for food and constant access to training resources. Shame that being a cyborg, I didn't really need any of what was being thrown my way. I would gladly delegate these privileges to Saitama but sadly the Association were keen on flexing their bureaucratic muscle as long as it meant one less S-Class mouth to feed.

"Welcome back. Kombu soup is ready on the table for you. I know it's not much but-"

I fumble for justification but was cut short by Saitama. He never was one for overdrawn excuses. He too, was well aware of the money situation.

"Yeah, yeah I get it."

He sits at the table, an audible crunch of his back followed by a slight grunt and arch of his figure. The room we shared was tiny enough that you could have heard the sounds at any angle. I know exactly why, too:

"Sorry for burning the futon again." I say without any eye contact.

Due to reasons unknown, the mechanical components of my body had been malfunctioning every time I put myself into hibernation. I experience intense dreams, repeating in my head every night. Depictions of Saitama standing motionless when I first met him; fighting that mosquito monstrosity. The only discernible features I can make out involve him with his right arm and palm outstretched. Chiselled chest and biceps. Nude. Everything from the waist down is blacked out completely.

As I awake, it's too late to do anything but extinguish the flaming mattress before the fire detector kicks in and evacuates the whole block. There were enough people who disliked Saitama, the least I could do was dispose of the embarrassing mess I made and contributed further to the problem.

"Hm. We need to fix this soon, we're barely breaking even on rent and we can't keep buying more beds. Does Kuseno have any leads?" Saitama responds.

While I'm not interested in what the Association were offering me, the only person that I could depend on helping me was Dr. Kuseno; the man who modified me with augmentations. Even he had no idea what to do. One idea involved swapping my augments and arsenal, but that would have meant repeating physical tests and the threat of being reassigned to different classes. We quickly decided that even the slightest change in my chassis or architecture could result in a multitude of negative consequences. At least worse than what's happening right now.

"No, unfortunately. He's working as hard as he can to achieve some sort of positive outcome." I said with a sunken head.

Before I know it, we had both tore through dinner. Well, not that there was much to begin with.

"Well, keep at it. I'm going to have a bath. Least I can do for this back of mine." Saitama cocks his head in my direction as he heads towards the bathroom.

I haven't had the liberty of feeling it for a while now, but a good night's sleep can do wonders for a human body. I ponder about the burning beds as I glance toward Saitama as he tosses his cape to his side. While he hasn't lost any noticeable muscle mass due to his strict training regimen, the circles around his egg-shaped eyes had darkened, suggesting he hadn't had the rest his body craved.

 _Mmm, no muscle mass lost at all. That's good._

I was lost in thought and caught myself staring directly at Saitama's figure, noticing even the tiniest of contours from the other side of the room, paying extra attention to his lower figure; his calves, his thighs, his d…

I snap out of it just in time, the boosters on the back of my arms whirring ever so quietly. Thankfully Saitama was none the wiser and headed into the bathroom, keeping the door slightly ajar.

 _What the hell was that all about? Why did my components react that way?_

These were the thoughts I mulled over as I cleaned up the remnants of dinner. From the pots, bowls of rice and kombu, I struggle to shake off this feeling that I'm missing something. As I've been stringent on my rent money, Saitama and I reached an agreement where I'd take on the majority of chores in the house while he performs most of the patrols assigned by the Hero Association. It was an arrangement that I was still a little unsure about, as dealing with all these stressors had taken a toll on my ability to prioritise. It was only until a few moments after cleaning the last bowl until it finally hit me.

 _Shit! I was meant to collect Saitama's costume for washing!_

I race towards the bathroom and barge through the door in a desperate bid to quickly collect his garb.

"Teacher, your costume!"

But it was too late. Instead I am greeted with a sight I had become accustomed to through my dreams of late. Saitama was yet to enter the bath and facing my direction. The visual I had been so used to, the naked apparition of him finally unblackened from his waist down. It took me a while to get used to the idea that this was real and happening right in front of my very eyes. My metal parts suddenly heating up from the sight. It was then I found myself muttering uncontrollably:

 _"Target acquired."_

I push Saitama against the wall as he braces himself against the basin, slight cracks emanating from the sides due to the force I was using. His expression was blank, which was always par for the course with him. I couldn't exactly figure out if he approved of this behaviour or not, but he could tell by my lustfully contorted face that I had something particular in mind. I then blurted out:

"Teacher, I would like to… _spar_ with you."

There was nothing but silence as I awaited his response. No noise was made aside from the running water of the bath, soon to be overflowing.

"OK." Saitama finally declared with a deadpan stare.

His glare followed me as I knelt towards his crotch, staring at his man noodle. I gasped slightly to find that the lack of curtains certainly did not match the lack of drapes; Saitama's crotch had a full head of pubic hair. Maybe his training regimen wasn't as intense as he let on, as it seemed to have spared some of the hair on his body. It seems there were further secrets to discover about this man.

Now was not the time to get caught up in such details, I had to discover why I was heating up at the mere sight of his log. I grasped it with both hands to inspect it from every angle, that was until my hands started to move in an up-and-down motion by themselves, occasionally administering a flick of the wrist motion as I completed each stroke. I had not planned to get too brash but I had plenty more up my sleeve.

I quickly raise my head to see how Saitama is reacting. Same reaction to how I pinned him against the wall just minutes ago, perhaps even a little disapproving than usual. I've seen this look many times in combat, and times when I've trained with him, which only means one thing.

"Huh, are you done yet?" Saitama spoke with conviction.

 _"Only just getting warmed up, Teacher."_ I blurt out, the full length mirror next to me revealing a shit eating grin I frequently wore before my fateful encounter with Saitama. Perhaps I wasn't as humble as I thought I was.

I up the ante by throwing a few of my signature Machine Gun Blows at the base of Saitama's drooping schlong. Maybe this is exactly what he is into. After a series of repeated hooks I stare at his face to find a more determined look on his face. Not one of disapproval, but intense focus. He's interested, now we're getting somewhere.

 _Until then._

Before I could figure out my next swing, my arm had been caught mid-punch by something incredibly coarse and tough. I look down to find Saitama's gargantuan member standing tall and deflecting every subsequent blow I threw. Every attempt to retaliate ended up a successful parry in his favour.

My futile attempts at making Saitama submit results in a bellow of laughter from him. This made me angrier and my body temperature hotter. I was quickly becoming embarrassed by the fact that I was no longer the aggressor.

Before I could notice, Saitama's throbbing sausage had become encased in some kind of clear secretion. Each time I punched, my fists had fizzled and cooled in temperature. This was _not right_! The hotter my body was, the better my attacks!

Afraid of losing control, I decided to pull my trump card right then and there. I tensed my arms and grabbed Saitama's hairy monster mid-parry with both hands. It was then that I kick-started my boosters and as they buzzed and whirred, simultaneously activated the heat beams in my palms. I immediately placed my mouth on the tip of his one-eyed monster and used my tongue to initiate a wicked dance of finesse to keep it held securely in place.

 _Got you now Saitama. Now submit!_

My hands heat up as they rigorously ride up and down the shaft of Saitama. I notice him wincing slightly as the friction of my jerking hands combined with the applied heat dissipating the sheath of fluid that once enveloped him. Before long, I keep perfect rhythm as the hair around his pubic region begins to burn away.

"Huh?"

Saitama looks down towards where I was doing my handiwork, surprised to find not a strand of public hair he was so proud to have kept despite the consequences of his rigorous training.

"What have you done?!" Saitama raises his voice for the first time in a while.

My first reaction was to look up and even then, there wasn't enough time to respond to what transpired. Saitama reached around and hoisted me by the back of my pants; the force in which he uses completely tears away both my slacks and underpants. Using this amount of force in sparring is not like him at all.

 _This wasn't good._

"That was the last batch of hair I had on my body! You better have enough rent money to fix your ass by the time I'm done with it!"

As I'm raised from behind, my last cohesive moments were looking at the full length mirror adjacent to me; Saitama's face a distorted combination of anger and humiliation. For some reason, it made my body hotter in preparation for what was to come.

Before I could respond, Saitama forces my body, pressing down from my shoulders as something coarse stuffs my ass, filling every inch.

 _Oh. Oh. Oh!_

That was it. All it took was one thrust. Everything went dark.

 _Hmmmnngh._

That one thrust made me remember the dream I was experiencing those countless nights. Saitama's naked body had always been obscured from the waist down.

 _Aaaaaaaagh_

It was only then that the darkness had cleared, revealing an object a thick as one of his forearms.

 _aaaaaaaAAAAAAAAAAAAAAAA_

It then finally hit me. His elusive third "arm" was inside of me.

 _INCINERAAAAAAAAAAATE!_

I yell at the top of my lungs as my internal fans, boosters and components reach capacity. My propellers act as jet propulsion and I send myself barrelling into the bathroom ceiling, hitting several layers of concrete before the trajectory sends me flying into the night on a journey of ecstasy.

The last words I heard from _him_ as I left the confines of Z-City was "NO! I'M BACK TO ONLY ONE PUUUUUUUMP!"

It wasn't too long until I crash landed, conveniently at Dr. Kuseno's lab. He repaired whatever damages I had upon impact. However, he made the stunning revelation that an unknown substance had creeped into my system and while I lay dormant undertaking repairs, I had refrained from heating up or burning anything.

"A Central Processing Unit regulates its temperature by transferring its heat through a thermal paste away from itself. Your core acts in a similar way, as this milky-white substance acts as a coolant. If I can acquire further samples, this can be administered to you on a permanent basis; preventing you from having any further accidents while hibernating!" The doctor deduced.

Once I put two and two together, it was probably best to play dumb and never reveal the true source of this mystery coolant. After all, it would have kept him working on better augments that would prevent me from overheating in the near future.

As for me, I'm back at home with Saitama. Business is finally picking back up now that the Hero Association have rebuilt major parts of their headquarters. Since our little incident, I've incorporated my own regimen to counter Saitama's that will help with his premature quirks. 100 pumps a day. Nothing more, nothing less. He's not quite there, but progress is being made at an alarming rate.

While I'm no longer burning any furniture, my chores have shifted to more… non-negotiable acts should I forget to pay rent on time.

I set dinner on the table just as Saitama arrives after a fruitful day of patrol. Looking a lot more limber now that he has a futon to sleep on again.

"Genos, it's time to _spar_ again." Saitama exclaims.

"We don't need to, I finally have enough rent money this week." I establish assertively.

"I don't care." He retorts while making direct eye contact. A small smirk forms in the corner of his mouth as he lowers a hand to his crotch.

 _Target Acquired._


End file.
